COMPARISONS OF FOUR TECHNIQUES FOR PRAWN (Macrobrachium rosenbergii) NURSERY REARING¹

Prawn ( Macrobrachium rosenbergii ) postlarvae (average weight 0.04 g) were stocked at 40/m 2 into circular plastic nursery pools with a surface area of 7.3 m 2 and water depth of 0.5 m. The use of fertilizers in place of feeds, pre‐treatment of fertilized pools with trichlorfon to reduce predacious insects and/or competitors and the use of additional substrate were evaluated for prawn nursery rearing. After a 35‐day nursery period, average survival and weight in fertilized pools with additional substrate were 65% and 0.301 g, in fertilized pools with additional substrate and pre‐treated with trichlorfon 66% and 0.231 g, in pools receiving feed with additional substrate 74% and 0.352 g, and in pools receiving feed but having no additional substrate 83% and 0.305 g. There were significant differences in survival and growth between the treatments. The results of this study suggest prawn growth and survival were improved with feeds, while improvements from a trichlorfon pretreatment or additional substrate were not substantial.